Even before it is fully edited, a new film about the Civil War is proving controversial.

“Civil War: The Untold Story” from Denver’s Great Divide Pictures will air on public TV in 2014. Narrated by “Downton Abbey’s” Elizabeth McGovern, a great “get” for the producers, the documentary will be different from Ken Burns’ 1990 film in several ways:

‹ Re-enactments of battles and other scenes make it feel cinematic, more Steven Spielberg (“Saving Private Ryan”) than Burns (actors reading letters and speeches over still photos).

‹ It focuses on the Western Campaign which, overshadowed by the much more famous campaign in the East, is where, it argues, the war was won and lost. Never mind Gettysburg and Antietam. Take a look at Shiloh and Vicksburg.

Advance word on the documentary, which carries the tag line “It’s not just about who we were then, it’s about who we are now,” has inspired hate mail from neo-Confederate groups on the radical right.

On the eve of the 150th anniversary of the bloodiest battle of the war, the Denver filmmakers behind the project are getting threats from fringe groups who don’t like the premise: that the war was fought over the concept of slavery. While that may be what most of us learned in school, certain holdouts insist it was about “states’ rights.”

The debate resonates today. “The fact of a black president brings it to the surface,” producer-director Chris Wheeler said.

The arguments endure. Does a state have the right to secede from the union? Is government intended to work for the people, stepping into private affairs when necessary? Do all people have the same civil rights? And do the 1 percenters get to call the shots?

The five-hour documentary will “break new ground by examining the war through the lens of the Western Campaign,” according to Wheeler, whose previous films include the award-winning “How the West was Lost” and “Our Time in Hell: the Korean War.”

Wheeler also aims for this new Civil War exploration to bring into focus the “relatively unknown roles African-Americans played in the conflict.”

A preview of the film suggests it will be violent and bloody enough to attract the younger audience seeking action, while scholarly enough to satisfy historians. Archival photos, interviews with prominent Civil War academics and authors, and re-enactments combine to tell the story.

The filmmakers, Wheeler and senior associate producer Holly Johnson, have a preliminary commitment from American Public Television, a program distributor, to offer the film to the more than 350 public TV stations nationally in the first quarter of 2014. They are still looking for underwriters.

Landing McGovern to narrate was fortuitous. The commitment from the actor — Lady Cora, Countess of Grantham! — is a coup for the producers, not only for the name recognition she brings but as a potential way to cross-promote the documentary within “Downton Abbey” and vice versa. The opportunity arose because Wheeler’s previous films, including “How the West Was Lost,” employed Peter Coyote as narrator. Coyote and McGovern share the same agent; a connection was made. Wheeler planned to fly to England to tape McGovern’s narration this month.

The highly directed battle re-enactments were “a growing experience for us because we’re documentarians,” Wheeler said. Those shoots involved hundreds of re-enactors, not actors but Civil War geeks.

Great Divide has been in the documentary business for more than 20 years. Recently the company has been producing films for visitor centers for more than 25 national parks — which is how they won the rights to film battlefield re-enactments on location in Shiloh National Military Park, Chickamauga/Chattanooga National Military Park and Kennesaw Mountain National Battlefield Park.

“We want to tell the story that goes beyond military and civil war buffs,” Wheeler said. “It’s been a generation since Ken Burns’ “Civil War.” People need to hear this story again.”

The fact is, nearly 700,000 lives were lost when the nation spun out of control from 1861-85, he notes. Hard feelings endure a century and a half later, particularly in the South.

“The Civil War did not bring a birth of new freedom,” Peter S. Carmichael, Civil War professor at Gettysburg College says in the preview clip. “The Civil War gave birth to profound and divisive questions that Americans continue to grapple with today.”

It’s an ambitious project by local filmmakers at a time when there are fewer outlets for this sort of documentary.